Electromagnetic apparatus



Dec. 7, 1937. P. H, CRAGO 2,101,166

ELECTROMAGNETI C APPARATUS Filed June 50, 1934 INVENTOR Paul H Crago WHIS. ATTORNEY Patented Dec. 7, 1937 UNITED STATES PATENT OFFICEELECTROMAGNETIC APPARATUS Application June 30, 1934, Serial No. 733,282

7 Claims.

My invention relates to electromagnetic apparatus, and particularly toapparatus of the type involving a direct current magnet having anoperating winding and an armature.

One object of my invention is the provision of novel and improved meansfor delaying the operation of the armature when the operating windingbecomes connected with a source of current.

I will describe one form of apparatus embodying my invention, and willthen point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form ofapparatus embodying my invention.

Referring to the drawing, the reference character R designates anelectromagnetic device, which, as here shown, is a direct current relayhaving the usual operating winding 3, armature i operated thereby, andcontact finger 2 operated 2 by the armature I. This contact finger 2co-operates with a lower contact member 2 to form a back contact 2-2 andwith an upper contact member 2 to form a front contact 2-2.

The winding 3 may be connected with and disconnected from a battery B bymeans of a contact 4. A resistance RI is interposed between the batteryand one terminal of winding 3, although if the internal resistance ofthe battery is high enough this resistance may be omitted.

Connected in multiple with the winding 3 is a condenser C, and, as hereshown, the branch path including this condenser also includes backcontact 2---2 of relay R. When front contact 2-2 is closed, condenser Cis connected with a discharge path, which, as here shown, includes asecond resistance R2.

When contact 4 becomes closed, current from battery B charges thecondenser C until the voltage across this condenser is above the pick-upvoltage of relay R, at which time relay R operates armature 2 to openthe back contact and to close the front contact. The opening of the backcontact 2-2 opens the branch path around winding 3, and the closing offront contact 22 closes the discharge path for condenserC,so that thecharge in the condenser is immediately dissipated. When contact 4 againbecomes opened, the armature l of relay R will immediately release,whereupon the parts of the apparatus will be restored to the positionsin which they are shown in the drawing.

Condenser C may be connected directly across the terminals of winding 3without the interposition of contact 2-2 but when this is done, relay Rwill be slow to release its armature upon'the opening of contact 4,because of the slow decay of energy in the condenser C through winding3. Furthermore, slow pick-up will not be obtained immediately afterrelease, because condenser C will not then be fully discharged. Byinterposing 5 the back contact in the branch path for this condenser,and by providing a discharge path through the front contact, I haveaccomplished quick release of relay R and also slow pick-up if contact 4becomes closed immediately after relay 10 R has released.

Although I have herein shown and described only one form of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the 5 scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

,1. In combination, a source of direct current, 20

an electromagnetic device having an energizing winding and an armatureoperated thereby as well as a back contact operated by said armature,means for connecting said winding with and disconnecting it from saidsource, and a condenser 25 connected in multiple with said windingthrough said back contact for delaying operation of said armature whensaid winding becomes connected with said source. 2. In combination, asource of direct current, an electromagnetic device having an energizingwinding and an armature operated thereby as well as a back contactoperated by said armature, means for connecting said winding with anddisconnecting it from said source, a condenser con- 35 nected inmultiple with said winding through said back contact, and a resistanceconnected in series with said condenser for delaying operation of saidarmature when said winding becomes connected with said source.

3. In combination, a source ofdirect current, an electromagnetic devicehaving an energizing winding and an armature operated thereby as well asa front and a back contact operated by said armature, means forconnecting said wind- 45 ing with and disconnecting it from said source,

a condenser connected in multiple with said winding through said backcontact for delaying operation of said armature when said windingbecomes connected with said source, and a dis- 50 charge path for saidcondenser including said front contact.

4. In combination, a source of direct current, an electromagnetic devicehaving an energizing winding and an armature operated thereby as 55 Oilwell as a front and a back contact operated by said armature, means forconnecting said winding with and disconnecting it from said source, acondenser connected in multiple with said winding through said backcontact, a resistance connected in series with said condenser fordelaying operation of said armature when said winding becomes connectedwith said source, and a discharge path for said condenser including saidfront contact.

5. In combination, a source of direct current, an electromagnetic devicehaving an operating winding, means for at times energizing said windingfrom said source, a contact controlled by said device and closed whensaid operating winding is deenergized, and a circuit connected with saidwinding and including a condenser as well as said contact for delayingthe operation of said device.

6. In combination, a source of direct current, an electromagneticdevice, a contact controlled by said device and closed when the deviceis deenergized, means for at times energizing said device from saidsource, and a circuit including a condenser and said contact fordelaying the energization of said device. a

7. In combination, a source of direct current, an electromagnetic devicehaving an energizing winding and an armature operated thereby as well asa back contact operated by said armature, means for at times energizingsaid winding from said source, and a circuit including a condenser andsaid back contact for delaying the ener- PAUL H. CRAGO.

